1. Field of the Invention
The present invention relates to a waste treatment apparatus. In particular, the present invention relates to a waste treatment apparatus for performing volume reduction-annihilation treatment by decomposing, by microorganisms, various raw waste such as vegetables, meats, and fishes, various plastic waste such as plastic bags and foamed trays, various paper waste such as paper bags, paper cartons, corrugated cardboard, newspaper, and paper diapers, and other waste.
2. Description of the Related Art
An organic waste treatment apparatus is been disclosed in Japanese Patent Laid-Open Publication No. Hei 9-1112 (Patent Document 1). In this organic waste treatment apparatus, microorganisms are added to organic waste, such as raw waste (leftovers, noodles, fishes, vegetable scraps, meats, fruits, chicken egg shells, fish bones, etc.), and the organic waste is decomposed into water and carbonic acid gas in a main body while the organic waste is agitated in the main body. Furthermore, in this organic waste treatment apparatus, a rotation shaft is provided slightly above a generally central portion of the main body. The rotation shaft rotates through a motor with a speed reducer, a sprocket, a chain, and other components. Provided in the rotation shaft are a plurality of agitating elements, such as paddles, for agitating the organic waste, such as raw waste, fed into the main body (see, for example, FIGS. 2 and 3 in Patent Document 1).
In this organic waste treatment apparatus, upon starting the motor with a speed reducer, the rotation shaft rotates, and the organic waste, such as raw waste, is agitated by the agitating elements, such as paddles. As the organic waste is agitated, the decomposition of the organic waste by the microorganisms added thereto is promoted and occurs uniformly, and the organic waste is decomposed into water, carbonic acid gas, and a very small amount of solid contents.
Furthermore, in this organic waste treatment apparatus, a circulation passage for circulating air in the main body is provided in an upper portion of the main body. Moreover, successively provided in the circulation passage are: a moisture removal device, such as an evaporator, for removing moisture in the air in the circulation passage; and an air heating device, such as a condenser or a heater, for heating the air from which moisture has been removed by the moisture removal device. Part of the air heated by the air heating device passes through the circulation passage and is supplied to and recirculated into the main body, and part of the air passes through an exhaust passage that is branched from the circulation passage and is discharged outside the main body through a deodorizing device provided in the middle portion of the exhaust passage (see, for example, FIG. 2 of Patent Document 1). In this case, foul odors are prevented from being discharged outside the main body.
However, when the agitating elements, such as paddles, used in such a conventional waste treatment apparatus (see, for example, FIGS. 2 and 3 of Patent Document 1) are used, the efficiency of agitating raw waste and other waste in a main body is not always high even if the organic waste is crushed by a crusher and then fed into the main body. For example, a bridge phenomenon occurs in which the end portion of a puddle carries ball-like clusters of raw waste and other waste, and thus the raw waste and other waste cannot be agitated uniformly and efficiently. Furthermore, the raw waste remains in a portion along the inner wall of the main body. Therefore, the efficiency of agitating raw waste and other waste is reduced, and a problem occurs in that decomposition treatment (fermentation treatment) by microorganisms takes a very long time.
In such a conventional waste treatment apparatus, the problem described above occurs even when only the so-called raw waste, such as food scraps and leftovers, is treated. Therefore, when raw waste is agitated in the main body together with plastic waste including plastic bags and plastic packaging containers such as styrofoam trays and/or paper waste such as newspaper, corrugated cardboard, and paper diapers, the agitation efficiency is further reduced. That is to say, such a conventional waste treatment apparatus is not suitable for simultaneously subjecting waste including raw waste mixed with plastic waste and paper waste to decomposition treatment (fermentation treatment) by microorganisms. Therefore, in such a conventional waste treatment apparatus, at least plastic waste must be separated from raw waste and/or paper waste, and thus a lot of effort is required.